It has become well established that there are major public health benefits from regular endoscopic examinations as an aid to the early detection of disease of internal structures such as the alimentary and excretory canals and airways, e.g., the colon, esophagus, lungs, uterus, bladder, bronchi, and other organ systems. A conventional imaging endoscope used for such procedures comprises a flexible elongated tube with a fiber optic light guide that directs illuminating light from an external light source to the distal tip where it illuminates the region (i.e., tissue, varices) to be examined. Frequently, additional optical components are incorporated to adjust the spread of the light exiting the fiber bundle and the distal tip. An objective lens and fiber optic imaging light guide communicating with a camera at the proximal end of the scope, or an imaging camera chip at the distal tip, produce an image that is displayed to the operator. In addition, most endoscopes include one or more working channels through which medical devices such as biopsy forceps, snares, fulgration probes, and other tools may be passed.
Conventional endoscopes are expensive hand assembled medical devices costing in the range of $25,000 for an endoscope and much more for the associated operator console. Because of this expense, these conventional endoscopes are built to withstand repeated disinfections and use upon many patients. Conventional endoscopes are generally built of sturdy materials, which decreases the flexibility of the scope and thus can decrease patient comfort. Furthermore, conventional endoscopes are complex and fragile instruments that frequently need expensive repair as a result of damage during use or during a disinfection procedure.
Low cost, disposable medical devices designated for a single use have become popular for instruments that are difficult to sterilize or clean properly. Single-use, disposable devices are packaged in sterile wrappers to avoid the risk of pathogenic cross-contamination of diseases such as HIV, hepatitis, and other pathogens. Hospitals generally welcome the convenience of single-use disposable products because they no longer have to be concerned with product age, overuse, breakage, malfunction and sterilization. One medical device that has not previously been inexpensive enough to be considered truly disposable is the endoscope, such as a colonoscope, bronchoscope, gastroscope, duodenoscope, etc. Such a single-use or disposable endoscope has now been developed and is described in U.S. patent application Ser. No. 10/811,781, filed Mar. 29, 2004, now patented as U.S. Pat. No. 7,413,543, and in a U.S. Continuation-in-Part patent application Ser. No. 10/956,007, filed Sep. 30, 2004, now patented as U.S. Pat. No. 7,578,786, that are assigned to Scimed Life Systems, Inc., now Boston Scientific Scimed, Inc., and are hereby incorporated by reference.
Vascular and lymphatic malformations, otherwise known as varices, pose an extremely challenging treatment dilemma for physicians and for their patients. If varices burst, they can be obliterated by injecting a drug that turns the varices into sclerotic tissue, known as sclerotherapy. The use of sclerotherapy to treat and prevent active hemorrhage has been demonstrated to be one effective intervention; however, there are potential complications associated with the use of various sclerosing agents, such as post-injection fever, swelling, and varying degrees of discomfort. In view of the potential complications associated with sclerotherapy, the development of endoscopic band ligation is now considered a primary intervention for managing active bleeding. The principle behind the development of endoscopic variceal banding is similar to band ligation of hemorrhoids and involves placing elastic bands around the varices. The object of such ligation is to position an elastic band over the targeted region, stretch a band over the region, and release it so that it contracts, thereby applying inward pressure on the section of tissue caught within the band. The effect of the pressure applied by the band is to stop circulation through the targeted tissue, thereby causing the tissue to die. The body eventually sloughs off the banded tissue, or the tissue may be removed later by an endoscope.
Conventional variceal banding systems typically consist of an outer housing cylinder that is snapped-on, frictionally coupled, or otherwise removably attached to the distal end of a conventional endoscope. An inner banding cylinder is then mounted within the outer housing cylinder, with a single band and an associated trip wire threaded through the biopsy channel of the endoscope. While the method of variceal banding has become increasingly popular among physicians, the conventional banding system has several drawbacks. For example, because the banding systems generally contain a single ligation band, the procedure often involves withdrawing and reloading the device with one or more additional ligation bands. In addition, the conventional systems require the user to manually control the trip wire, thereby resulting in a lack of consistent band deployment. Further, the conventional banding systems have poor visualization capabilities due in part to the limitations of conventional video imaging systems and to the visual obstruction from the banding cylinder. Finally, the conventional banding system is removably attached to a conventional endoscope and, therefore, assembly of the endoscope with the banding device must be done prior to each clinical use followed by disassembly and sterilization of the components after each use.